Water actuated time delay switch



June 5 M. M. CAROTHERS I 2,794,880

WATER ACTUATED nus DELAY 'swrrcn Filed July 30, 195s FlG.3

'INVENTOR. MELVIN M. CAROTHERS A TTO/PNEYC United States Patent C WATER ACTUATED TIME DELAY SWITCH Melvin M. Car-others, Eugene, Greg. ApplicationJuiy 3t 1956, Serial, No. 600,918

4 Claims. (Cl. 2fi084) This invention relates to a water actuated time delay switch and more particularly to a switch suitable for mounting in the flush tank of a toilet so as to start an exhaust fan when the toilet bowl is flushed and to stop the fan after a period of time which may be several Time delay is obtained by controlled flow of water intosaid casing through an orifice. While the switch of such prior application is entirely operable, it has now been found that-a simplertime delay switch can be provided by eliminating such float valve and discharging air trapped within ,the switch casing through a metering orifice in the upper portion of such casing.

The switch of the present invention includes a vertically elongated switch casing having a closed upper end and a permanently open lower end. The casing is positioned within the flush tank of a toilet so that its lower portion extends below the level of the water in such flush tank when the tank is full. switch which is closed when the flush tank is emptied. That is to say, any water within the switch casing drains therefrom as the water level in the flush tank. is lowered and the downward movement of a float in the casing is employed to close an electric circuit for starting a fan motor. As the Water rises in the flush tank after a flushing operation, air is trapped in the switch casing and such air is controllably exhausted from the interiorof the casing through a metering orifice positioned in the upper portion of the switch casing as the water continues to rise. The metered discharge of air delays the rise of water in the switch casing so that there is a time delay before the float rises to open the electrical circuit and stop the fan motor.

It is therefore an object of the present invention to provide an improved water actuated time delay switch which does not require a water actuated float valve.

Another object of the invention is to provide a simple water actuated-time delay switch with a minimum of moving parts and which can be mounted in the flush tank of a toilet to start a fan when the toilet is flushed and to stop the fan after a time delay.

A further object of the invention is to provide an exhaust fan switch for the flush tank of a toilet which depends for its operation upon the trapping of air in a switch casing and the metered exhaust of air from such casing in order to provide a time delay.

Other-objects and advantages of the invention will appear in the following description of a preferred embodiment given in connection with the attached drawings of which:

Fig. l is a front elevation of the switch of the present The casing contains a float actuated 2,794,880 Patented June 4, 1957 invention showing the manner of mounting it in the flush tank of a toilet;

Fig. 2 isa top view of the structure shown in Fig. 1;

Fig. 3 is a vertical section through the. switch of the present invention on an enlarged scale and taken on the line 3-3 of Fig. 2 with the switch holding clamp structure omitted;

Fig. 4 is a horizontal section taken on the line 4-4 of Fig. 3;

Fig; 5 is a schematic diagram showing a suitable circuit for the switch of the present invention when employed to start and-stop an exhaust fan; and

Fig. 6 is a view similar to Fig. 1 showing a modified switch structure.

Referring more particularly to the drawings, the switch of Figs. 1 to 5 includes a vertically extending casing 10 which may be of any desired shape, but which preferably is circular in horizontal cross section. As shown in Fig. 1, the casing 10 may be secured to the vent pipe 12 of a flush tank of a toilet. by means of clamps 14 held in engagement with the outersurfaces of the casing '10 and thevpipe 12 by means of clamp screw 16. The clamps 14 and screw 16, as well as the casing 10, are preferably made of a non-corrodable metal, such as brass, although they may be madeof any non-corrodable material, for example, the casing 10 may be made of a suitable plastic material.

The casing. 10 may have a cap 18, preferably of elec trical insulating material, such as a molded plastic material. The cap is suitably secured to the upper end of the casing and closes such upper-end except for a metering orifice 20 in the top portion of the cap. The under surface of the cap 18 has a pair of contact members 22 secured thereto by screws 24, the contact members 22 being insulated from each other and extending downwardly and then horizontally within the casing 10 in generally parallel relationship. A float 26 is positioned within the casing 10, and has a centrally positioned rod 28 extending. upwardly between the contact members 22 and terminating at its upper end in a circular contact element 30 positioned above the horizontal portions of the members 22. It will be apparent that the float 26 will cause the contact element 30' to complete an electric circuit between the contact members 22 when the water level in the casing 10 is below the float 26, and that the contact element 30 will be lifted above the contact members 22 to break such electric circuit when the water in the casing 10 reaches a level sufliciently high to move the float 26 upwardly. The float 26 is preferably of electrical insulating material or at least has an upper surface of such material to prevent closing of the electric circuit when the float is in its upper position.

The screws 24 may also be employed to connect the contact members 22 to wires 32 and 34 such that establishing a circuit between the contact members 22 completes a circuit through the actuating coil -36 of a relay or contactor shown in Fig. 5. The remainder of such circuit includes the secondary winding 38 of a stepdown transformerhaving a primary winding 40 connected across the conductors 42 of an electric power line. Energization of the relay coil 36 closes a circuit through the fan motor 44 which is also connected across the conductors 42.

In operation the switch of Figs. 1 to 5 is normally open when the flush tank is full of Water, since the water level in the casing 10- of the switch is sufficiently high to lift the contact element 30 from engagement with the contact members 22. Under these conditions the fan motor 44 is not supplied with electric power. When the toilet is flushed, the level of the water in the flush tank rapidly decreases below the lower end of the casing 16. Almost as soon as the water level starts to fall in the flush tank, the float 26 falls to cause the contact element 39 to close the electric circuit through the contact members 22 to start the fan motor. As soon as the level of the Water falls substantially below the lower end of the casing 10, the casing rapidly empties of water since it is of sulficient diameter that a column of air moves upwardly adjacent one side of the casing. The water level in the flush tank then rises and when it reaches the bottom of the casing 10, air is trapped within the casing 10. Such air is gradually exhausted through the metering orifice 20 as the water rises around the casing 10 and there is a time delay before the water reaches a sufliciently high level within the casing to raise the float 26. The extent of this time delay may be adjusted by adjusting the level of the casing 10 relative to the highest level the water reaches in the flush tank. The lower the casing 10 of the switch is positioned in the tank the shorter the time delay and the higher the switch casing is positioned in the flush tank the longer the time delay. As shown in Fig. 1, the casing may be provided with indicia on its upper portion for alignment with the water level reached when the fiush' tank is full and indication whether the time delay will be short, medium or long.

A modified form of switch is shown in Fig. 6 and includes the casing 10. A modified form of cap 46 has a depending standard 48 secured to its lower surface adjacent one side of the casing. At the lower end of the standard there is pivoted at 49, a float supporting arm 50 which extends across the casing and is inclined downwardly when in its lowermost position shown in Fig. 6. A float 52 in the form of a hollow ball is shown as being secured to the end of the arm 50, although a free hollow ball, such as a table tennis ball, with suitable means for preventing it from falling out of the casing 10 can also be employed. Upon rise of water in the casing 10, the float moves upwardly to cause the arm 50 to assure an upwardly inclined position with respect to its pivot. A mercury switch element 54 is suitably secured to the "arm 50, for example, by a spring clip 56, so that an electric circuit is opened when the arm is in the upwardly inclined position just described and closed when the arm is in the position shown. The mercury switch element of Fig. 6 may be suitably connected by flexible conductors 58 to the conductors 32 and 34, shown in the circuit diagram of Fig. 5, instead of the open contact type of switch shown in the other figures of the drawing, and the cap 46 of the switch of Fig. 6 may also contain the metering orifice 20 for controlling the exhaust of air trapped in the casing 10. The operation of the switch of Fig. 6

is the same as that of Figs. 1 to 5, except that the circuit through relay coil 36 is closed and opened by the mercury switch element 54.

It will be apparent that I have provided a simple switch for making and breaking a circuit after a time delay in response to changes of water level in a toilet flush tank, which switch is reliable in operation and involves a minimum of moving parts. 7 V

I claim:

1. A time delay switch for mounting in a tank in which the level of the water is varied between upper and lower water levels, said switch comprising a vertically extending casing, means for supporting said casing in said tank with the lower end of said casing below said upper water level and above said lower water level, said lower end of said casing having an opening therein of suflicient size that water will rapidly drain from said casing when the water in said tank falls below said lower end, said casing having a metering orifice in its upper portion for the controlled discharge of air trapped in said casing to delay the rise of water in said casing when the water rises in said tank, a float in said casing having an upper and lower position and movable between said lower and said upper positions by rise and fall of water respectively in said casing, and electrical contact means actuated by said float to complete an electric circuit when said float is in one of said positions and to break said circuit when said float is in the other of said positions.

2. A time delay switch for mounting in a tank in which the level of the water is varied between upper and lower water levels, said switch comprising a vertically extending casing, means for adjustably supporting said casing in said tank with the lower end of said casing below said upper water level and above said lower water level, said lower end of said casing having an opening therein of suflicient size that water will rapidly drain from said casing when the water in said tank falls below said lower end, said casing having a metering orifice therein above said upper water level for the controlled discharge of air trapped in said casing to delay the rise of water in said casing when the water rises in said tank, a float in said casing having an upper and lower position and movable from said lower to said upper position by rise of water in said casing when the water in said tank approaches its upper level, and electrical contact means actuated by said float to complete'an electric circuit when said float is in its upper position and to break said circuit when said float is in its lower said position.

3. A time delay switch for mounting in a tank in which the level of the water is varied between upper and lower water levels, said switch comprising a vertically extending casing, means for supporting said casing in said tank with the major portion of said casing including its lower end positioned below said upper water level and with its lower end above said lower water level, said lower end of said casing having an opening therein of suflicient size that water will rapidly drain from said casing when the water in said tank falls below said lower end, said casing having a metering orifice in its upper portion for the controlled discharge of air trapped in said casing to delay the rise of water in said casing when the Water rises in said tank, a float in said casing having an upper and lower position and movable from said lower to said upper position by rise of water in said casing when the water in said tank approaches its upper level, and electrical contact means actuated by said float to complete an electric circuit when said float is in one of said positions and to break said circuit when said float is in the other of said positions.

4. A time delay switch for mounting in the flush tank of a toilet for starting a fan when the toilet bowl is flushed and stopping said fan after a time delay, said switch comprising a vertically extending casing, means for supporting said casing in said tank for vertical adjustment and with a substantial portion of the length of said casing below the upper water level in said tank, said casing having an opening in its lower end of suflicient size that water will rapidly drain from said casing when the Water in said tank falls below said lower end, said casing having References Cited in the file of this patent UNITED STATES PATENTS Gulick Sept. 5, 1933 Carothers Nov. 27, 1956 

